Microtubules are hollow polymers made up of tubulin subunits. Neurons, like other eukaryotic cells, contain a pool of free tubulin subunits and a pool of the microtubule polymers. These two pools dynamically exchange with one another such that microtubules undergo bouts of assembly and disassembly.n neurons, microtubules are also nucleated at the centrosome (located in the cell body of the neuron), but the microtubules are then severed from the centrosome so that they can be deployed into axons and dendrites.
If the parent makes this election, the child does not have to file a return. Earned and Unearned Income. If a child has both earned and unearned income, he or she must file a return (2016 and 2015) if: unearned income was over $1,050; earned income was over $6,300, or
Other Reasons to File a Tax Return. Regardless of your gross income, you are generally required to file an income tax return if any of the following are true: 1  You had net self-employment income of $400 or more. 2  You had unemployment income.3  You owe Alternative Minimum Tax.4  You owe household employment taxes.here are several reasons why you may want to file or efile a tax return even if you do not meet the minimum income requirements: 1  If you had taxes withheld from your pay, you must file a tax return to receive a tax refund. 2  If you qualify, you must file a return to receive the refundable Earned Income Tax Credit.